1. Field of the Invention
The present invention relates generally to a system and method for ultraviolet disinfection and, more particularly, to a system and method for ultraviolet disinfection of appliances.
2. Description of the Prior Art
UV Mechanism of Action
It is well known in the art to use ultraviolet light (UV) for the microbial disinfection of liquids and surfaces. Ultraviolet light, at the germicidal wavelength of 253.7 nanometers, alters the genetic (DNA) material in cells so that bacteria, viruses, molds, algae and other microorganisms can no longer reproduce. The microorganisms are considered dead, and the risk of disease from them is eliminated. As the UV lamps irradiate a fluid or surface in UV disinfection systems, the microorganisms are exposed to a lethal dose of UV energy. UV dose is measured as the product of UV light intensity times the exposure time within the UV lamp array. Microbiologists have determined the effective dose of UV energy to be approximately about 34,000 microwatt-seconds/cm2 needed to destroy pathogens as well as indicator organisms found in wastewater. Typical prior art disinfection systems and devices emit UV light at approximately 254 nm, which penetrates the outer cell membrane of microorganisms, passes through the cell body, reaches the DNA and alters the genetic material of the microorganism, destroying it without chemicals by rendering it unable to reproduce.
Ultraviolet light is classified into three wavelength ranges: UV-C, from about 200 nanometers (nm) to about 280 nm; UV-B, from about 280 nm to about 315 nm; and UV-A, from about 315 nm to about 400 nm. Generally, UV light, and in particular, UV-C light is xe2x80x9cgermicidal,xe2x80x9d i.e., it deactivates the DNA of bacteria, viruses and other pathogens and thus destroys their ability to multiply and cause disease, effectively resulting in sterilization of the microorganisms. Specifically, UV xe2x80x9cCxe2x80x9d light causes damage to the nucleic acid of microorganisms by forming covalent bonds between certain adjacent bases in the DNA. The formation of these bonds prevents the DNA from being xe2x80x9cunzippedxe2x80x9d for replication, and the organism is neither able to produce molecules essential for life process, nor is it able to reproduce. In fact, when an organism is unable to produce these essential molecules or is unable to replicate, it dies. UV light with a wavelength of approximately between about 250 to about 260 nm provides the highest germicidal effectiveness. While susceptibility to UV light varies, exposure to UV energy for about 20 to about 34 milliwatt-seconds/cm2 is adequate to deactivate approximately 99 percent of the pathogens.
Regulation of Drinking Water Standards
Exposure to pathogens does not always cause disease; whether drinking contaminated water could produce disease depends on the type and quantity of pathogen ingested and the health (nutritional and immunological) status of the person ingesting the pathogen. However, the use of low-level antibiotics to improve feed conversion in domestic animals has led to the emergence of antibiotic-resistant pathogens. In recognition of this problem, U.S. governmental agencies are seeking to improve the control of food production through such programs as the Hazard Analysis Critical Control Point (HACCP).
Traditionally, the most common means of maintaining water used in household appliances at an acceptable purity for long periods of time is through the addition of reactive chlorine. Unfortunately, certain microorganisms, such as Cryptosporidium, have developed resistance to reactive chlorine, and have now returned as a public health problem. Additionally, dumping of contaminated waste such that a municipal water treatment facility is overtaxed has resulted in ineffective water purification with the result that pathogens are delivered to humans in the drinking water. Although persons might prevent such contamination through the use of purified drinking water, other appliances that use municipal water may be contaminated with the pathogens and consequently expose the user to the pathogen. Thus a need exists for appliances and other devices whose contact surfaces and/or interior contents can be easily sterilized.
A system for UV light treatment of appliances has been described by the inventor in U.S. patent application Ser. No. 09/724,180. This system includes transmission of UV light to appliances via fiber optic transmission lines for the purpose of microbial disinfection. However, no appliances or storage devices are currently equipped with a portal for connection to a fiber optic transmission line for the purpose of UV sterilization.
Thus, there remains a need for appliances and container devices that contain a portal to which a fiber optic transmission line can be attached for the purpose of UV sterilization.
The present invention is directed to a portal system for appliances and containers for the attachment of a fiber optic transmission line for the purpose of UV sterilization. One object of the present invention is to provide a portal-based appliance system for ultraviolet disinfection (UW) incorporated within appliances for providing disinfection along with the appliance function, the system including at least one portal for receiving UV light input into the appliance from a UV light source.
Another object of the present invention is to provide a portal system for ultraviolet (UV) disinfection of containers that includes at least one portal included as part of the container housing for providing disinfection within the container.
Accordingly, one aspect of the present invention is to provide a portal-based appliance system for ultraviolet disinfection (UV) of appliances, wherein the system includes an appliance having at least one portal for receiving UV light input.
Another aspect of the present invention is to provide a portal system for ultraviolet disinfection (UV) of containers, wherein the system includes at least one portal included with the container housing for receiving UV light input into the container from a UV light source.
These and other aspects of the present invention will become apparent to those skilled in the art after a reading of the following description of the preferred embodiment according to the present invention when considered with the drawings.